Video narration
Are moving and staying still really opposites? Imagine you're sitting on a train, watching another beside you. As it seems to slide backward, you may think that train is moving. But look at the platform. If the platform stays fixed while the trains shift, your train is moving. And you are still in your seat relative to the train, while moving with it relative to the ground. That is the turn: motion is not something an object carries by itself. It is a change in position over time relative to a chosen reference point-a fixed thing you compare against. So the same seat is still relative to the train, but moving relative to the ground. Both descriptions are correct, because they use different reference points. So, are you moving or sitting still? On the train, you can be both-depending on what you measure against.